1. Field of the Invention
The present invention relates a composition having a high content of xanthophyll esters, where the xanthophyll ester component of the composition is comprised of a high proportion of trans-lutein esters. The present invention also provides methods of making and using such a composition.
2. Description of the Background
The xanthophylls of marigolds flowers (Tagetes erecta) occur acylated with fatty acids (Alam et al., 1968; Phillip and Berry, 1975). These xanthophyll esters belong to a group of natural compounds known as carotenoids and are widely distributed in nature. Xanthophyll esters are mainly fatty acid esters [e.g., palmitate and myristate esters: J. of Food Sci., 51 [4] 1093 (1986)] of carotenoids such as lutein and zeaxanthin. The marigold flower is the richest source of trans-lutein esters found in nature. Dried and ground marigold flowers have been used commercially since 1966 as a coloring agent in animal feed, and, since 1969, they have been used as a starting material for the production of marigold extracts.
Lutein ester is the main xanthophyll pigment, responsible for the yellow/orange color of fruits such as oranges, peaches, papayas, etc. Xanthophyll esters are generally found in nature as trans-xanthophyll isomers.
Recent scientific research has shown that marigold extracts containing lutein esters may be used as nutritional supplements. Among other possible uses in nutrition and medicine, it has been found that lutein esters are specially beneficial in the treatment and prevention of some types of cancer, and in the treatment of a condition known as age-related degeneration of the macula in the human eye (MAD) (see “The effect of Dietary Lutein on growth of mammary tumor BALB/c Mice” The FASEB Journal 11 2586 (1997); International Journal of Cancer 63 18-23 (1995)). It has been reported that consumption of lutein and zeaxanthin reduces the risk of developing MAD up to 40% in mature people (Seddon et al., J. Med. Assoc. 272 [18] 1439-1441 (1994)). Several indicative studies have demonstrated that lutein esters increase the macular pigment density and that the bioavailability is even better than free lutein. (Herbst S, Bowen P, Hussain E, Stacewicz-Sapuntzakis M, Damayanti B, Burns J., Evaluation of the bioavailability of Lutein (L) and Lutein ester (LD) in humans” The FASEB, Journal, 1997; 11:2587 (Abstr.)).
When using lutein esters for human consumption, it is preferable to have the highest possible concentration in the product, and the highest possible trans-lutein content. This is especially important in the nutraceuti cal industry, notably for tableting or elaborating oil formulas.
Several attempts have been made in the past to achieve a high xanthophyll ester concentrate with high trans-lutein content, for example the U.S. Pat. No. 4,048,203 to Phillip describes a process of purification of xanthophyll esters using isopropylic alcohol at 75° C. However this heat treatment results in an undesirably large proportion of the less-bioavailable cis-lutein isomer and a low concentration paste of around 309.25 g/kg (approximately 56% by weight of xanthophyll esters) and a trans-lutein content of 88% by HPLC. Furthermore the resulting paste is sticky and hard to handle.
U.S. Pat. No. 6,191,293 to Levy suggests the treatment of an oleoresin with isopropylic alcohol at 20° C. The resulting product obtained by this procedure has allegedly higher concentration (50% by weight of xanthophyll esters), but with the disadvantage that the marigold petal oleoresin needed for this procedure is not common, and the resulting xanthophyll ester content in the best case is still low (69% by weight of xanthophyll esters).
When using a normal oleoresin derived from whole flowers, instead of petals, and performing the method suggested by U.S. Pat. No. 6,191,293, the resulting paste contained 234 g/kg (approximately 42% by weight of xanthophyll esters) and a trans-lutein content of 84.61%, by HPLC.
U.S. Pat. No. 6,737,535 to Kumar, suggests the use of 2-propanone to obtain a xanthophyll ester concentrate. This procedure results in a product with a concentration of 279 g/kg (approximately 51% by weight of xanthophyll esters) and a profile of 93.4% of trans-lutein, by HPLC.
Even though the profile in this concentrate is better than U.S. Pat. No. 6,191,293, the concentration in this product is still low (<80% by weight of xanthophyll esters) compared to the present invention (>80% by weight of xanthophyll esters as described below).
In view of the foregoing, it is evident that a much better product can be obtained with higher concentration and better chromatographic profile, i.e., a higher proportion of trans-lutein esters.